Drill press



Nov. 27, 1956 B. w. BENBOW 2,771,797

DRILL PRESS Filed May 5, 1952 3 Sheets-Sheet 1 INVENTOR. Buff/'5 Wfienbow ATTORNEY! Nov. 27, 1956 B. w; BENBOW 2,77

DRILL PRESS Filed Kay 5, 1952 ,3 Sheets-Sheet 3 PIE E IN V EN TOR.

flurf/s fienbow A TTORNE Y5 DRILL PRESS Burtis W. Benbow, San Leandro,(Iaiif.

Application May 5, 1952, Serial No. 286,115

11 Claims. (131. 77-29) This invention relates generally to drillingapparatus and particularly to machines commonly known as drill presses.

In my Patent 2,483,613 I have disclosed a drill press which incorporatesa clutch in such a manner that when the drill is pressed against a workpiece, the clutch is automatically engaged to drive the drill. Anarrangement of this type is advantageous in that the drill is drivenonly when it is pressed against the work, thus reducing drill breakageto a minimum and making possible better control of drilling operations.

It is an object of the present invention to provide certain improvementsto the drill press disclosed in said Patent 2,483,613.

More particularly it is an object of the present invention to provide animprovement which will enable one to lock the main vertical shaft of themachine head to thereby facilitate operation of the chuck to engage ordisengage drills.

Another object of the invention is to provide novel means whereby theclutch can be engaged without the necessity of urging the drill againsta work piece.

Another object of the invention is to provide an improved change-speeddrive means for a. drill press.

Additional objects and features of the invention will appear from thefollowing description in which the preferred embodiments of theinvention have been set forth in detail in conjunction with theaccompanying drawing.

Referring to the drawing:

Figure l is a plan view illustrating a drill press incorpo rating thepresent invention.

Figure 2 is a side elevational view of the drill press shown in Figure1.

Figure 3 is a plan view like Figure 1 but showing parts in a diiferentoperating position.

Figure 4 is an enlarged cross-sectional detail illustrating the clutchand the parts associated with the same.

Figure 5 is an enlarged cross-sectional detail taken along the line 5-5of Figure 2.

Figure 6 is a cross-sectional detail taken along the line 6-6 of Figure5, with the parts in a diiferent operating position.

Figure 7 is a side elevational view in section illustrating anotherembodiment of the invention.

Figure 8 is a plan view of the drill press shown in Figure 7, withcertain parts in section.

The drill press illustrated particularly in Figures 1 and 2 of thedrawing consists of a vertical standard '10, which is carried by asuitable base (not shown). A head frame 11 is slidably carried by thestandard 10, and can be clamped at any desired elevation by turning theclamping lever 12. The head frame 11 carries the driving motor 14, theshaft of which is attached to the multi-diameter sheave 16. A suitabledriving belt 17 engages one of the diameters of the sheave 16, and alsoa cooperating diameter of the sheave 18, the latter forming a part ofthe head assembly.

Instead of mounting the motor 14 directly upon the 1 2,771,737 PatentedNov. 27, 1956 head frame 11, it is shown secured to a mounting plate 19.This plate is pivotally attached to 21 to the head frame 11, and is alsopivotally attached to the link 22.

At the front of the machine there is a guard 23, which normally extendsover the front half of the sheave 18, and which is pivotally carried bythe bolt or screw 24. An arm 26 is secured to the guard 23, and has itsfree end pivotally attached to the link 22.

The arrangement described above is such that when the guard 23 is in thenormal position illustrated in Figures 1 and 2, the distance betweencenters of sheaves 16 and 18 is such that the belt 17 is tensioned fornormal driving. When guard 23 is swung forwardly and to one side asillustrated in Figure 3, the mounting plate 19 and the motor 14 areswung toward the front of the machine, as illustrated in Figure 3, thusshortening the distance between the centers of sheaves 16 and 18, andcausing the belt 17 to be slackened. The slack is suflicient to enablethe belt to be shifted to any sheave diameter desired, thus permittingthe operator to select a desired speed of operation. After the desiredbelt position has been selected, the guard 23 is swung back to theposition illustrated in Figures 1 and 2, whereby the motor is swungrearwardly to cause the belt 17 to be tightened. It will be noted inFigure 1 that the arm 26 passes dead center position with respect to thelink 22, thus retaining the guard in closed position.

Additional parts of the drill head assembly are illustrated in Figures4, 5 and 6. The sheave 18 is journaled upon a sleeve 28, which is fittedin the portion 29 of the machine frame. The sleeve 28 also forms abushing through which the shaft 31 extends. The upper portion of shaft31 is fluted, and has a splined drive with respect to the clutch cone32. The cone 32 is adapted to have driving engagement with the innerconical surface 33 of the sheave 18.

Another vertical sleeve 34 is slidably fitted within the frame portion36, and generally embraces the shaft 31. A suitable thrust bearing, suchas the ball bearing assembly 37, is interposed between the upper end ofthe sleeve 34 and the cone 32. A member 38 is fixed to the sleeve 34,and is bored horizontally to provide a iournal for the shaft 39. Thisshaft has one exterior end attached to the operating handle 41, and alsocarries a pinion 42. A sleeve 43 is slidably fitted within the sleeve34, and forms a journal for the lower portion of the shaft 31. One sideof the sleeve 43 is formed to provide the gear rack 44, the teeth ofwhich engage the teeth of the pinion 42. The lower end of the shaft 31carries a chuck 46 which serves to grip a drill or like tool 47.

With the arrangement described above the turning of pinion 42 byswinging the lever 41 serves to raise or lower the sleeve 43, and tolikewise raise or lower the shaft 31. If the drill 47 carried by thechuck 46 engages a work piece, downward force applied upon the lever 41causes the shaft 39 and the pinion 42 to be urged upwardly, togetherwith member 33 and the sleeve 34. The upwardly applied force urges thecone 32 against the inner conical surface 33 of the sheave 18, toestablish a driving connection. Thus under such conditions, and assumingthat the motor is in operation to drive the sheave 18, torque is appliedto the shaft 31 for a drilling operation. When the drill is elevatedfrom contact with the work, driving engagement of the clutch cone 32with the conical surface 33 is immediately interrupted, whereby thedrill automatically stops.

In Figure 4 the drill shaft 31 is shown in its uppermost position. Inthis position the shaft is locked against rotation. The locking meansmakes use of a member 48, which is carried by the stationary cap 49.Member 48 is provided with one or more keys which engage within theflutes of shaft 31. Locking of shaft 31 against rotation in 3 its upperlimiting position facilitates release of clamping operations of thedrill chuck 46.

In certain types of drilling operations it is desirable to engage theclutch without the necessity of urging the drill against the work piece.My drill press incorporates means for this purpose, including the partillustrated in Figures 5 and 6. The member 38 is provided with a sideextending portion 51, which overlies a portion 52 that is integral withthe frame part 36. Camming means is interposed between the portions 51and 52, and utilizes the metal ball 53. The upper part of this ball isnormally seated in a recess formed in the plug 54. The plug isadjustably threaded in the portion 51. The lower portion of the ball isnormally seated in a recess formed in the upper end of a plunger 56. Theplunger is slidably fitted within a sleeve 57 which is adjustablythreaded in the portion 52. A compression spring 58 normally urges theplunger 56 upwardly against the ball. Downward movement of the plunger56 against the spring 53 is limited by the upper end 59 of thesleeve 57.

Operation of the parts illustrated in Figures 5 and 6 is as follows: Thecompression spring normally causes the ball 53 to be clamped within thetwo accommodating recesses formed in the plug 54 and the plunger 56.Therefore the plug and plunger 54 and 56 are normally maintained inalignment, although the upward thrust of the spring 58 is not sufiicientto force the clutch to engaged position. If the hand lever 41 is swungto the left or to the right, there is a camming action upon ball 53which serves to increase the vertical distance between the portions 51and 52, thus raising member 38 together with the sleeve '34 to move theclutch cone 32 to engaged position. Such a camming position isillustrated in Figure 6. Immediately upon release of the lever 4-1, theparts return to the nor mal aligned position illustrated in Figure 5.

Since the lever 41 serves both for the purpose of low ering the drill,and for causing the clutch to be engaged without the necessity ofcontacting the drill with a work piece, it will be evident that theover-all operation of the drill press is greatly facilitated. The drillpress operator may utilize the automatic features of the clutch tocontrol turning of the drill, and at the same time the drill can bestarted and stopped as desired, independently of contact of the drillwith the work piece, and by manipulation of the same operating lever 41.

In the embodiment of the invention illustrated in Figures 7 and 8, thehead frame 61 is carried by the standard 10, and is vertically bored toreceive the sleeve 62. This sleeve has a gear rack 63 which is engagedby a pinion 64. The sleeve 62 forms a journal for the vertically movableshaft 66, the lower end of which carries the drill chuck 67. A member 68is bored horizontally to journal the shaft 69, and this shaft serves tomount the pinion '64. One exterior end of this shaft is attached to theoperating lever 71. Member 68 is carried by the vertical pin or bolt 72,the upper end of which is attached to the lever 73. The rear end of thislever is pivoted at 74 to the frame 61, and the forward end embraces theshaft 66, and engages a thrust bearing assembly 75, which underlies theclutch cone 76 and sheave '77.

The lower end of member 68 has a rearwardly extending portion 78, whichoverlies a portion 7 9 which extends from the frame 61. Portions 78 and79 carry the parts of the'camming means illustrated in Figures 5 and 6,including particularly the cam ball 53.

Thedrill press illustrated in Figures 7 and 8 operates as follows:Assuming that the sheave 77 is being driven, movement of the lever 71 ina vertical direction serves to raise or lower the drill, and when thedrill is pressed down against a work piece, member 68 is urged upwardly,thus causing the lever 73 to press upwardly against the thrust bearing75, to thereby move the clutch cone 76 to engage position. When thelever 71 is swung to the left or to the right, member 63 pivots aboutthe axis of bolt 72, and this causes the ball 53 to exert a cammingaction to move the portions 78 and 79 apart in a vertical direction.This likewise applies upward force -to the lever 73 to move the clutchcone 76 to engaged position.

it will be evident from the foregoingthat I have provided a drill presshaving many desirable features. It has the advantages of automaticcontrol of the drill which are disclosed in my Patent 2,483,613, and atthe same time the drill can be driven without the necessity of forcingthe drill against the workpiccqand by manipulation of the same operatinglever which is used for raising or lowering the drill. Movement oftheshaft -31 to locking position as illustrated in Figure 4 isdesirable inthat it greatly facilitates manipulation of the drill clamping chuck.The change speed mechanism facilitates rapid changes in the drivingspeed for the drill, with a minimum number of operating parts forreleasing the belt tension.

1 claim:

1. in a driil press, a frame, a vertical shaft carried by the frame, thelower end of the shaft being adapted for attachment to a drill, a sleeveconcentric with the'shaft and through which the shaft extends, saidshaft being journaled in said sleeve, a member movable vertically withrespect to the frame, a pinion carried by said memher, an operatinglever connected to said pinion whereby the pinion is turned when theoperating lever is moved in a vertical direction, a gear rack formed onsaid sleeve and engaging said pinion, drive means for the shaftincluding sheave concentric with the shaft, friction clutch meansadapted to be engaged for causing the sheave to drive the shaft, saidfriction clutch means including a clutch member concentric with theshaft and movable between engaged and disengaged clutching positionresponsive to vertical movement of said member, whereby swinging saidlever in a vertical direction causes the drill to be lowered against awork piece and to cause said friction clutch means to be engaged todrive the drill when the drill is pressed against the work piece, andcamming means acting between said member and said frame and serving tomove the member in a vertical direction responsive to swinging saidlever in a horizontal direction, whereby such movement of said membercauses engageent or disengagement of said friction clutch meansindependently of pressure between the drill and the work piece.

2. A drill press as in claim 1 in which said member is carried by asleeve portion which is fitted concentrically about said first namedsleeve and is rotatable about the axis of said shaft.

3. In a drill press, a frame, a vertical spindle carried by the frame,the lower end of the spindle being adapted for attachment to a drill,drive means for the shaft, said drive means includinga multi-diametersheave disposed concentric to said shaft and another driving sheavespaced rearwardly from said first named sheave, the sheaves beingconnected by a driving belt, a sheave guard pivotally carried by theframe for swinging movement between out-of-the-way and guard positionsrelative to the first named sheave, and means responsive to swingingmovement of said guard for moving said second named sheave toward andaway from the first sheave.

4. A drill press as in claim 3 in which said second sheave is attachedto the shaft of an electric driving motor, and in which the drivingmotor is carried by a mounting plate, the mounting plate being pivotallyattached to the frame to enable movement toward and away from the firstnamed sheave.

5. In a drill press, a frame, a vertical shaft carried by the frame, thelower end of the shaft being adapted for attachment to a drill, a sleeveconcentric with the shaft and through which the shaft extends, saidshaft being journalled in said sleeve, another sleeve concentric withsaid first named sleeve and slidably and rotatably mounted thereon so asto be vertically and rotatably movable with respect to the frame andsaid first named sleeve, a member fixed to said last named sleeve, :1pinion carried by said member, an operating lever connected to saidpin-ion whereby upon rotation of the operating handle in a verticalplane the pinion is rotated, a gear rack formed on said first namedsleeve and engaging said pinion, drive means for the shaft including asheave concentric with the shaft, friction clutch means adapted to beengaged for causing the sheave to drive the shaft, said friction clutchincluding a clutch member concentric with the shaft and movable betweenengaged and disengaged clutching positions responsive to the verticalmovement of said second named sleeve, whereby rotation of said leverdownwardly in a vertical plane causes the drill to be lowered against awork piece and to cause said friction clutch means to be engaged todrive the drill when the drill is pressed against the work piece, andcamming mean-s acting between said member and said frame serving to movethe member in a vertical direction responsive to rotation of the memberabout a vertical axis, said member being rotated about its vertical axisby swinging said lever in a horizontal direction whereby such movementof said member causes engagement or disengagement of said frictionclutch means independently of pressure between the drill and the workpiece.

6. A drill press as in claim 5 wherein the camrning means includes aball bearing and means mounted in the frame for urging said ball bearingupwardly against said member, the upward force on said ball bearingbeing insufficient to cause engagement of said clutching means.

7. A drill press as in claim 5 together with means for engaging theupper portion of the shaft, said means serving to lock the shaft againstrotation when the shaft is raised to its upper limiting position.

8. A drill press, a frame, a vertical spindle or shaft carried by theframe, the lower end of the shaft being adapted for attachment to adrill, the upper portion of the shaft being fluted, means for raisingand lowering the shaft, drive means for the shaft, friction clutch meansautomatically engaged to cause the drive means to turn the shaftresponsive to pressing a drill against the work piece, and key meansengaging the upper fluted portion of the shaft serving to lock the shaftagainst rotation when the shaft is raised to its upper limitingposition.

9. In a drill press, a frame, a shaft carried by the frame, one end ofthe shaft being adapted for attachment to a drill, means for driving theshaft, clutch means for engaging or disengaging the drive means withrespect to the shaft, means including an operating lever for raising orlowering the shaft with respect to a work piece, means for causing saidclutch means to be engaged responsive to pressing the drill against awork piece by movement 'of the operating lever in one plane, and meansoperated by movement of said operating lever in a different plane forengaging said clutch means independently of the means for causing theclutch means to be engaged responsive to pressing the drill against thework piece.

10. A drill press as in claim 1 together with a lever having one endpivotally connected to said frame, the lever being movable in a verticaldirection to effect engagement or disengagement of said friction clutchmeans and in which said member is pivotally connected to said lever andis moved in a vertical direction as said member is moved.

11. In a drill press, a frame, a vertical spindle or shaft carried bythe frame, the lower end of the shaft being adapted for attachment to adrill and the upper end of the shaft having flutes, means for raisingand lowering the shaft, drive means for the shaft, friction clutch meansautomatically engaged to cause the drive means to turn the shaftresponsive to pressing the drill against a work piece, and means forengaging the upper portion of the shaft serving to lock the shaftagainst rotation when the shaft is raised to its upper limitingposition, said last named means comprising a cap mounted on said frameand adapted to receive the upper end of the shaft, and a keyed membermounted in said cap and adapted to engage the fluted portion of saidshaft to lock said shaft against rotation.

References Cited in the file of this patent UNITED STATES PATENTS542,695 Stover et a1. July 16, 1895 595,850 Flickinger Dec. 21, 1897663,055 Weinman Dec. 4, 1900 1,437,570 Vaughn Dec. 5, 1922 2,063,101Johnson Dec. 8, 1936 2,089,363 Haas Aug. 10, 1937 2,483,613 Benbow Oct.4, 1949 2,557,330 Wilger June 19, 1951

